The present invention relates to shelter systems for use in emergency situations, providing temporary shelter for persons who are trapped in a hostile environment.
More specifically, the invention relates to systems and devices for providing breathable air for shelters used to protect humans from unsafe atmospheres, such as those which are deficient in oxygen, or which contain unsafe levels of carbon monoxide, methane, or other toxic chemicals, including toxic industrial chemicals or chemical, biological, or radiological warfare agents.
Typical events which could cause the local atmosphere to become unsafe for human respiration include mine or tunnel emergencies, fires, terrorist activity, acts of war, chemical spills or other industrial accidents, and accidents at nuclear power plants. These events could take place in a mine, a tunnel, or a building. They could also occur outside, where such events could produce an atmospheric plume which is unsafe for breathing.
Political and criminal events in the early twenty-first century have highlighted, to an unprecedented level, the threat of a terrorist attack by “weapons of mass destruction”, such as chemical, biological, or radiological agents, or toxic industrial chemicals. Mine emergencies, in which the atmosphere inside the mine becomes unsafe for human respiration, have taken the lives of numerous miners throughout the history of underground mining. Fires in high-rise buildings, both commercial and residential, have caused the atmosphere above the level of the fire to become unsafe for human respiration. The result has been loss of life due to asphyxiation from toxic chemicals or inhalation of smoke.
For the above reasons, systems for protection of persons from the above-described events have become highly desirable.
An example of an emergency shelter for use in a hostile environment is shown in international patent publication No. WO 2005/086613, the disclosure of which is incorporated by reference herein. The above-cited document describes a collapsible shelter which can be quickly configured to provide a breathable atmosphere in which persons trapped in an emergency situation can survive.
The present invention provides a further improvement over the emergency shelters of the prior art.